There is a central macro in CRuby, RUBY_VM_CHECK_INTS, which is a very hot path for the Ruby runtime. It’s an important part of how threads are managed, and it’s called constantly. I was curious just how often it was called, and it turned out CRuby comes with some handy debugging functionality for just this scenario. Inside of debug_counter.h, I changed #define USE_DEBUG_COUNTER 0 to #define USE_DEBUG_COUNTER 1 and added this line later in that file: RB_DEBUG_COUNTER(rb_vm_check_ints) The...
